Irrigation Volume Research Articles

Soil aeration using air injection in a citrus orchard with shallow groundwater

Soil aeration is considered the third most important factor affecting soil fertility (after water and nutrient availability). The main reasons for poor soil aeration are slow drainage, excessive precipitation or irrigation, or a sealing soil cover. Shallow groundwater impedes drainage by reducing the downwardly hydraulic gradient, which consequently increases the water content of the soil in the root zone, thus limiting soil aeration. In this study, we examined the effects of different parameters (e.g., soil texture, depth of groundwater table) on the severity of oxygen deficiency in the root zone of a mature Valencia orange (Citrus sinensis) grove planted above shallow groundwater. In addition, we examined the effect of the O2 stress level on tree growth, yield, and fruit quality. We also evaluated the effects of air injection and of irrigation intensity on tree growth, yield, fruit quality, and O2 concentration in the soil’s air, and looked into the (technical and economic) feasibility of air injection into the soil. We found that insufficient soil aeration significantly inhibited tree growth and reduced the yield. The soil texture (i.e., clay content) had a substantial effect on the yield, mainly because of its effect on the soil’s water retention. While soil O2 concentration slightly increased by air injection, the differences in tree growth, yield, and fruit quality parameters were not significant. The O2 concentration of the soil air alone was found to be a poor quantifier of soil aeration status. The Damkholer number (Da), evaluated from the measured soil O2 profiles and groundwater table depths is a superior quantifier for the prevailing aeration status. It can also be used for analyzing the effect of irrigation water quality on soil aeration status and respiration rates.

Antiseptic Use in Orthopaedic Wounds

Objectives: The aim of this study is to review the available literature addressing the safety and efficacy of antiseptics in surgical wounds. The different antiseptic solutions, irrigation volumes, time scales and delivery methods have been compared so that evidence-based recommendations on antiseptic use in orthopaedic, foot and ankle surgical procedures can be proposed.
 Methods: A literature search was performed using the online databases Medline and EMBase to identify in-vitro and in-vivo studies pertaining to antiseptic use in an orthopaedic context. Terms including antiseptic, irrigation fluid, bacitracin, hydrogen peroxide, povidone-iodine and chlorhexidine were searched. Literature published in English from inception to July 2020 in which the full text was accessible was considered for inclusion. Cellular and animal studies were included on the basis that authors analysed antiseptic efficacy and/or toxic effect of antiseptic on cells present in orthopaedic wounds. Clinical studies that met the criteria for inclusion in this review assessed antiseptic use in a surgical context, with a focus on foot and ankle procedures. These included case reports, case series, case control, prospective and retrospective studies as well as randomised controlled trials. Studies were categorised as in-vitro, animal and human studies. Twenty-three, eleven and forty-four studies were identified as in-vitro, animal and human studies respectively. These have been summarised and presented herein in a narrative format.
 Results: There is strong evidence that skin preparation with antiseptics before orthopaedic procedures reduces the risk of post-operative infection.
 Conclusion: Routine prophylactic intra-operative antiseptic use should be performed with caution as they increase the risk of local and systemic complications. However, there is strong evidence supporting the use of antiseptics pre-operatively when preparing the skin. Determining the best antiseptic preparation remains a matter of debate since a single agent or solution is not effective against all organisms. Further research is therefore needed to assess the efficacy of antiseptics in prevention and treatment of infections.

Impact of Watershed Programmes in Bundelkhand Region of Madhya Pradesh, India: How Beneficiaries Perceive?

An ex- post study was conducted to assess the impact of watershed development programmes, and appraisal was made with perceptions of beneficiaries of respective watersheds. The water resources development activities were accorded the highest priority with the allocation of 42% of the total budget, followed by soil conservation activities with the allocation of 27% of the budget. The cumulative effect of land-based activities was observed in terms of an increase in cultivated area (34%), cropping intensity (44%), afforestation/plantation (34%), irrigation intensity (13%) as well as a decrease in current fallow (78%) and wasteland (35%). The value of crop diversification index and cultivated land utilization index were higher over pre-project situations, and higher value of crop yield index indicated the higher productivity levels for major crops in watershed villages. Positive and significant differences in various socio-economic attributes among watersheds and control areas like labour absorptions and income from crop enterprises also endorsed the positive effects of watershed-based interventions. However, yield enhancement, groundwater recharge, saving of resources and augmentation of income were the major benefits of various watershed-based interventions as perceived by the beneficiary households.

Comparison of the Efficacy of Transurethral Enucleation and Resection of the Prostate with Transurethral Resection of the Prostate for Medium Prostate Sizes

Objective: To compare the efficacy of the transurethral enucleation of the prostate (TUERP) to transurethral resection of the prostate (TURP) through a prospective randomized controlled trial. Materials and Methods: Between January 2016 and December 2019, 46 patients from a single center were divided into two groups, TURP and TUERP, using simple randomization. The perioperative and postoperative outcomes up to one year after surgery were evaluated. Results: The mean estimated prostate volume (PV) in the TURP and TUERP group was 40±22 mL and 41±18 mL, respectively. There were no statistical differences in the baseline characteristics between the two groups. The mean operative time was significantly longer in the TUERP group (71.95±33.96 minutes versus 50.85±26.78 minutes; p=0.024). The average weight of prostate resected in the TUERP group was higher but not statistically significant (18.87±14.95 g versus 15.15±11.07 g; p=0.39). The volume of fluid irrigation collected postoperatively was significantly lower in the TUERP group (13.98±10.01 liter versus 24.73±21.90 liter; p=0.04). No statistically significant differences were noted between the two groups in terms of the postoperative IPSS, QoL, Q max, PSA, postoperative Hct, and the length of hospital stay. Conclusion: The present study compared the surgical outcomes between the TUERP and the TURP techniques performed in medium prostate sizes. The authors concluded that TUERP resulted in a greater prostate tissue removal and, importantly, better intraoperative bleeding control. Keywords: Benign Prostatic Hyperplasia, Transurethral enucleation of the prostate

Influence of Mean Leaf Angles and Irrigation Volumes on Water Capture, Leaching, and Growth of Tropical Tree Seedlings

Research Highlights: The mean leaf angle and crown projection area can be used as criteria for grouping tree seedling species in different irrigation zones in tree nurseries with overhead microsprinkler systems, preventing water and fertilizer waste, and increasing growth. Background and Objectives: There are important gaps in current functional knowledge about how plant architecture, especially the mean leaf angles of tree seedlings, affect water and nutrient solution capture in overhead microsprinkler systems. These gaps contribute to water and fertilizer waste in tree nurseries. This research aimed to ascertain how mean leaf angles affect irrigation water capture, leaching, and the growth of tree seedlings given different volumes of irrigation. Materials and Methods: Nine species of tree seedlings with different mean leaf angles were submitted to four irrigation volumes (8, 10, 12, and 14 mm) applied daily by overhead microsprinklers in a split-plot design completely randomized. The variables leaching fraction, height, stem diameter, shoot, root, and total dry mass, Dickson quality index, crown projection area, root system quality, and leachate electrical conductivity were evaluated. Results: For species with mean leaf angles of −54, 31, 38, 42, 55, 57, and 58°, the 8 mm irrigation volume was sufficient to produce greater growth and less leaching. For species with angles of −56 and −14°, the 14 mm irrigation volume was required to produce greater growth. Conclusions: The tree seedling species with positive mean leaf angles facilitate irrigation water and nutrient solution capture, allowing the application of lower irrigation volume. On the other hand, some tree seedling species with negative mean leaf angles hinder irrigation water and nutrient solution capture, requiring the application of higher irrigation volume. When the tree seedling species have a negative mean leaf angle, but the crown projection area is small, the difficulty of water and nutrient solution reaches directly the substrate is attenuated.

A Remote Sensing Diagnosis of Water Use and Water Stress in a Region with Intense Irrigation Growth in Brazil

Western Bahia, Brazil, is a classic example of a region where intense irrigation growth has led to acute water stress situations in a few small basins. The water stress problem has the potential to grow regionally. However, there are currently no systematic field measurements of water withdrawn from rivers or groundwater to supply irrigation systems. In this work, we merge remote sensing and river gauge data to assess both the amount of water used for irrigation in Western Bahia and also its consequences for regional water stress, identifying water conflict situations and assessing water security. Remote sensing products used include time series of the normalized difference vegetation index, evapotranspiration, and rainfall. Field data include time series of river discharge and calibration data for crop status and actual evapotranspiration. From calibrated remote sensing products, three-day water balances were calculated for each center pivot using computations of irrigation depth and water uptake for irrigation, both individually at the center-pivot scale and integrated regionally. From these regional integrations, a simple water-use diagnostic indicated that three sub-basins presented the most critical conditions for water conflicts. An in-depth analysis of these sub-basins shows that, despite the high water stress, water use for irrigation has been steadily increasing, pushing the water use to its limits. This work demonstrates that the use of remote sensing products together with field data is a powerful tool for diagnosing water conflict situations. The limitations of this work relate to the absence of field data to validate the water uptake estimated and to the lack of additional long-term and high-quality river flow stations to provide diagnostics for all small basins in the region.

Comparison between infrapatellar and suprapatellar approaches for intramedullary nailing for the fractures of the tibial shaft.

This study aimed to compare the outcomes at the clinical and functional levels of suprapatellar (SP) and infrapatellar (IP) approaches for intramedullary nailing in treating tibial shaft fracture. Patients who underwent tibial shaft fracture intramedullary nailing by the SP approach or IP approach in a trauma center were retrospectively reviewed. The demographics, intraoperative fluoroscopy time, operation time, blood loss, irrigation volume, postoperative X-ray alignment, and complications of patients were compared between the two groups under different approaches. Lysholm knee score, visual analog score (VAS), and incidence of anterior knee pain (AKP) were assessed 1year after surgery. The study finally included well-documented 81 patients (38 SP versus 43 IP). The SP group exhibited significantly shorter intraoperative fluoroscopy time than that of the IP group (81.7 ± 14.5s vs. 122.0 ± 24.3s, P < 0.001). Both aspects recorded a precise reduction of the fracture: angulation (2.1 ± 1.2° vs 3.1 ± 1.5°, P < 0.05) and translation (0.6 ± 0.8mm vs 1.4 ± 1.5mm, P < 0.05) in the coronal plane in the SP group. However, the sagittal plane recorded no such change (P > 0.05). The Lysholm knee score was higher in the SP group than that of the IP group (87 ± 8 vs. 80 ± 15, P < 0.05). The SP group displayed an evidently lower average VAS score than that of the IP approach group (0.3 ± 0.8 vs 1.3 ± 1.4, P < 0.001). Six cases (16%) in the SP group and 16 cases (37%) in the IP group experienced AKP 1-year post-operation (P < 0.05). As far as complications are concerned, neither group showed any significant difference (P > 0.05). Compared with the IP approach, the application of intramedullary nailing through the SP approach in treating tibial shaft fractures can effectively shorten the intraoperative fluoroscopy time, correct coronal plane angulation and translation deformity, reduce the incidence of AKP and improve postoperative function.

Moist heat stress extremes in India enhanced by irrigation

Intensive irrigation in India has been demonstrated to decrease surface temperature, but the influence of irrigation on humidity and extreme moist heat stress is not well understood. Here we analysed a combination of in situ and satellite-based datasets and conducted meteorological model simulations to show that irrigation modulates extreme moist heat. We found that intensive irrigation in the region cools the land surface by 1 °C and the air by 0.5 °C. However, the decreased sensible heat flux due to irrigation reduces the planetary boundary layer height, which increases low-level moist enthalpy. Thus, irrigation increases the specific and relative humidity, which raises the moist heat stress metrics. Intense irrigation over the region results in increased moist heat stress in India, Pakistan, and parts of Afghanistan—affecting about 37–46 million people in South Asia—despite a cooler land surface. We suggest that heat stress projections in India and other regions dominated by semi-arid and monsoon climates that do not include the role of irrigation overestimate the benefits of irrigation on dry heat stress and underestimate the risks. Intensive irrigation in India cools the land surface, but increases the moist heat stress in South Asia, according to an analysis of observational datasets and meteorological models.

Treated wastewater irrigation promotes the spread of antibiotic resistance into subsoil pore-water

In the present study, we investigated the impact of treated wastewater (TWW) irrigation on the prevalence of antibiotic resistance genes (ARGs) in subsoil pore-water, a so-far under-appreciated matrix. We hypothesized that TWW irrigation increases ARG prevalence in subsoil pore-water. This hypothesis was tested using a multiphase approach, which consisted of sampling percolated subsoil pore-water from lysimeter-wells of a real-scale TWW-irrigated field, operated for commercial farming practices, and controlled, laboratory microcosms irrigated with freshwater or TWW. We monitored the abundance of six selected ARGs (sul1, blaOXA-58, tetM, qnrS, blaCTX-M-32 and blaTEM), the intI1 gene associated with mobile genetic elements and an indicator for anthropogenic pollution and bacterial abundance (16S rRNA gene) by qPCR. The bacterial load of subsoil pore water was independent of both, irrigation intensity in the field study and irrigation water type in the microcosms. Among the tested genes in the field study, sul1 and intI1 exhibited constantly higher relative abundances. Their abundance was further positively correlated with increasing irrigation intensity. Controlled microcosm experiments verified the observed field study results: the relative abundance of several genes, including sul1 and intI1, increased significantly when irrigating with TWW compared to freshwater irrigation. Overall, TWW irrigation promoted the spread of ARGs and intI1 in the subsoil pore-water, while the bacterial load was maintained. The combined results from the real-scale agricultural field and the controlled lab microcosms indicate that the dissemination of ARGs in various subsurface environments needs to be taken into account during TWW irrigation scenarios.

Introduction of the Nicotiana protein kinase (NPK1) gene by combining Agrobacterium-mediated transformation and recurrent somatic embryogenesis to enhance salt tolerance in cauliflower

Cauliflower is exposed to various biotic and abiotic stresses, including increased salinity due to the intensive irrigation of crops. Mitogen-activated protein kinase (MAPK) cascades are universal signal transduction modules that play important roles in regulating innate immune responses in plants. Based on involvement of tobacco MAP kinase kinase kinase (NPK1) in stress response, the effect of the expression of NPK1 transgene to NaCl salt stress tolerance in cauliflower KFRM4 lines was studied. The Agrobacterium tumefaciens-mediated transformation protocol, using EHA101(pSHX004) vector harbouring the NPK1 and phosphinothricin N-acetyltransferase (bar) genes, the cyclic somatic embryogenesis regeneration pathway, the application of acetosyringone (AS) during co-cultivation and a delayed phosphinothricine (PPT) selection procedure provided sufficient transformation efficiency of 7.33% without escapes. PCR analysis indicated the integration of both NPK1 and bar transgenes in regenerated cauliflower lines. Transgenic cauliflower lines, exposed to NaCl stress in vitro, showed higher growth rates, greater ability to retain chlorophyll and carotenoids, and increased osmotic regulation capacity compared with non-transformed control plants. The tolerance level of transformed lines correlated with the level of NPK1 gene expression estimated by RT-qPCR, and the L2 line with the highest NPK1 expression displayed the greatest tolerance to NaCl stress. None of the obtained cauliflower transformed lines grown in greenhouses showed any morphological or yield differences compared with non-transformed plants. Furthermore, the expression of the bar gene facilitated the tolerance of transformed lines to the total herbicide PPT, applied at concentrations 2–3 times higher than those routinely used for weed control in the crop field. The results underlined that constitutively expressing NPK1 can significantly contribute to enhanced salt stress tolerance in cauliflower, suggesting that this could be a promising basis for the creation of new stress tolerance cruciferous vegetable lines.

Correction to: Water dynamics at the urban soil-atmosphere interface—rainwater storage in paved surfaces and its dependence on rain event characteristics

The surface store governs the rainwater partition, e.g., water storage and evaporation on paved surfaces, especially for low-intensity and low-sum rain events, which account for the greatest part of the total rainfall in a temperate climate city like Berlin, Germany. The surface store S is a fixed value, dependent on surface relief and pore system characteristics. Contrary, in this study, the surface storage was assumed to depend also on the rain intensity, thus being variable from event to event. The surface store filling dynamics for dense (DP), porous (PP), and highly infiltrative (IP) paving materials were studied in a rainfall simulator. Irrigation intensities p ranged from 0.016 to 0.1 mm min−1 which represent the 25 to 88% quantiles of the rain event distribution in Berlin, Germany (1961 to 1990). Three surface stores can be separated: storage until initial runoff, Sf, at maximum filling, Sm, and for steady-state runoff, Seq—all of them can be regarded as effective stores depending on the aim of its use. The equilibrium store varies from 0.2 to 3 mm for DP, PP, and IP for the investigated rainfall intensities. For all pavers, the surface store depends on rainfall intensity, which was shown experimentally and confirmed by numerical simulation of the infiltration. We introduce a simple and robust method to describe Sf, Sm = f(p) for different pavers. Pavers can evaporate a multiple of their surface store per day, depending on the rainfall distribution, which implicates the need for high temporal resolutions in urban hydrology modeling. Pavers can evaporate a multiple of their surface store per day, depending on the rainfall distribution. That implicates the need for high temporal resolutions in urban hydrology modeling.

Prediction Method of Unsaturated Soil Water Content under Different Irrigation Intensities

Prediction Method of Unsaturated Soil Water Content under Different Irrigation Intensities

S0545 Impact of Colonoscopy Bowel Preparation and Intra-Procedural Volume of Colonic Irrigation (VOCI) on Serum Electrolytes

INTRODUCTION: A safe and effective bowel preparation (BP) is key to the performance of high-quality colonoscopy. Colonic irrigation is often used to clear stool and improve mucosal visualization. Procedures involving high volume water irrigation in other organs (e.g. TURP syndrome) have been associated with complications due to fluid shifts and electrolyte imbalance (nausea, emesis, hypotension, altered consciousness, mortality rate 0.2-0.8%). The effect of BP and volume of colonic irrigation (VOCI) on serum electrolytes requires further investigation. METHODS: An institutionally approved quality improvement prospective cohort study was undertaken at a large VA Medical Center. Veterans scheduled for outpatient colonoscopy between 03/2019 and 03/2020 were included. Data collected included demographics, baseline electrolyte levels (within prior 6 months), BP type, volume of clear liquid diet consumed (CLD) prior to colonoscopy, procedure details including VOCI, and complications. Serum chemistry panels were obtained from the intravenous catheter placed for sedation. After 8 weeks, data for 110 patients (pilot cohort) were analyzed. To confirm findings of significant electrolyte changes, observed rates of change and missing data were used to determine a validation cohort (n = 89). A +/-10% change in serum electrolyte level AND outside the normal range was considered significant. RESULTS: There was little variation among demographics and colonoscopy characteristic between the two cohorts (Table 1). Significantly more veterans had serum electrolyte abnormalities pre-colonoscopy compared to baseline in both cohorts (56.4% vs. 32.1% in pilot cohort, P < 0.001 and 53.9% vs. 28.9% in validation cohort, P < 0.001,Figure 1), with hypokalemia being the most common (12-16%). Rates of significant electrolyte changes (> 10%) were similar between cohorts with hypokalemia and hypocalcemia being the most common. Changes in Cr, Ca, and Phos were more pronounced in the validation cohort (Table 2). CONCLUSION: Significant pre-procedure serum electrolyte changes occurred following BP, especially hypokalemia. Post-procedure hypokalemia and, the increased incidences of post-colonoscopy hypocalcemia and hypophosphatemia in the validation cohort (cohort with higher average VOCI) suggest that VOCI is associated with electrolyte shifts. Further studies are required to assess the clinical impact of these electrolyte shifts and measures to avoid them.Figure 1.: Number of Unique Patients with Abnormal Labs at Given Times.Table 1Table 2

S3122 Factors Associated With Inadequate Colonoscopy Bowel Prep: Not the Patient but the Endoscopist, and the Role of Volume of Colonic Irrigation (VOCI)

INTRODUCTION: Colonoscopies with inadequate bowel preparation (BP) decrease the detection of adenomas and lead to earlier repeat follow up exams. There is no data on the impact of the endoscopists’ effort to achieve an adequate exam through water lavage and the endoscopists’ adequate BP rate. METHODS: This is a single center institutionally approved prospective study of eight endoscopists performing colonoscopy from 07/2017-03/2020. All endoscopists trained in the use of the Boston Bowel Prep Score (BBPS). We measured the volume of colonic irrigation (VOCI), defined as water infused in and fluid suctioned out for each colonoscopy. Data collection included patient demographics, factors associated with inadequate BP (BMI, constipation, tricyclic antidepressant and opiate medication use, diabetes), and colonoscopy findings (BBPS, VOCI in and out, polyp number, pathology). Only screening, surveillance and FIT positive cases were included. Inadequate BP was defined as a BBPS score of < 2 in any segment. We calculated the modified adenoma detection rate (mADR) defined as the proportion of screening or surveillance exams for which one adenoma was identified, as well as the modified adenomas per colonoscopy (mAPC) for each endoscopist. Comparisons between means were made using T-tests and ANOVA, with comparisons between proportions were made using Chi square. Coefficients of determination were calculated for linear correlations. RESULTS: Eight endoscopists performed 1223 colonoscopies (Table 1). Rates of adequate BP varied from 71.3% to 96.3%. There was no difference in VOCI in or out between high vs low adequate BP rate endoscopists (Table 2). There was no difference in VOCI in between high vs low mAPC endoscopists, but there was a statistically significant higher mean VOCI out (P = 0.035), although the volume was small (42 mL). mADR significantly differed among endoscopists but correlated with mAPC (R2 = 0.915). Rates of adequate BP did not correlate with mADR (R2 = 0.283). CONCLUSION: Despite standardized BP and prep scoring as well as equal distribution of inadequate BP patient factors, the rates of adequate BP still varied by 25% among endoscopists and was not affected by VOCI. These findings require further study but suggest that differences in rates of BP adequacy may have more to do with endoscopist factors than previously recognized, and may not correlate with other markers of endoscopist performance like mADR.Table 1.: Patient Demographics and Risk Factors for Inadequate Colon BP by EndoscopistTable 2.: VOCI, BBPS, mAPC, and mADR Rates by EndoscopistFigure 1.: Scatter Plot of Adequate Bowel Prep Percent by modified ADR.

Addressing the water conflict between agriculture and ecosystems under environmental flow regulation: An integrated modeling study

Modeling agriculture-impacted hydrological processes remains a challenge, as information on irrigation activities is often insufficient. This study developed modules for emulating high-resolution irrigation activities and representing water management policies in integrated hydrologic modeling. The new modeling approach was implemented in China's second largest endorheic river basin with intensive irrigation and exemplary environmental flow regulation. Pumping management is found to impact the hydrological regime at the basin scale and modulate the tradeoff between ecological services and agriculture. Limiting the groundwater level decline within 1 m would lead to a 3.9% decrease in cropland evapotranspiration in the middle basin and a 1.5% increase in the environmental flow towards the lower basin. Environmental flow regulation and pumping management have both synergistic and offset effects, reflecting a complex water-agriculture-ecosystem nexus in this basin. This modeling study suggests heterogeneous and dynamic groundwater management policies in water-limited areas and unravels threshold effects in the policies.

Effect of partial root-zone drying irrigation (PRDI) on the biomass, water productivity and carbon, nitrogen and phosphorus allocations in different organs of alfalfa

Partial root-zone drying irrigation (PRDI) can influence carbon (C), nitrogen (N), and P (phosphorus) allocations in annual crop plants. This study consisted of a two-factorial split-plot field experiment conducted on Huanghua farmland in western China, and it was focused on investigating the effects of PRDI on the biomass; water productivity; and C, N and P allocations in a perennial plant (alfalfa) from 2016-2017. The two factors were the irrigation mode (PRDI and conventional furrow irrigation (CFI)) and irrigation volume (70 %-I1, 85 %-I2, 100 %-I3 and 115 %-I4 of the alfalfa water requirement), in which the irrigation mode was the primary plot and the irrigation volume was the subplot. This study showed that PRDI decreased the alfalfa leaf biomass and increased the alfalfa root, stem biomass and water productivity but that it had no effect on the alfalfa shoot biomass at the end of the vegetative growth period in 2016 and 2017. PRDI increased the C and P concentrations in the roots and the N concentration in the roots, stems and leaves, and it led more C and P to be allocated to the roots and more N to be allocated to the leaves in 2016 and 2017. These results implied that C, N, and P allocation changes in different organs induced by PRDI may be one of the possible ways for alfalfa plants to adapt to the changing environmental conditions caused by PRDI.

The pitfalls of water potential for irrigation scheduling

The water potential (Ψp), has been widely used as an indicator of plant water status for irrigation management purposes. The simple infrastructure needed for its measurement and its direct relation to basic plant physiological processes, have contributed to the popularity of the methodology. When used for irrigation scheduling, it is commonly assumed that an unavoidable relationship exists between plant transpiration (T), soil water content and Ψp. Nevertheless, it is worth remembering that variations in Ψp are not solely related to changes in soil water content, but are also an expression of the interaction between the plant and its environment. We used a soil-plant-atmosphere-continuum (SPAC) model to highlight the importance of considering such interactions through a series of in silico experiments. Our analysis shows that evaporative demand, the hydraulic architecture of the plant, and the texture and depth of the soil play key roles in the final Ψp observed. To establish irrigation programs based on Ψp, without considering the environmental and plant factors that influence it, can create the paradox of having a plant that suffers greater water stress even when high irrigation volumes are applied. The conclusions from our in silico analysis provide some warnings that should be considered when using Ψp to schedule irrigation.

The influence of humic and fulvic acids on Cd bioavailability to wheat cultivars grown on sewage irrigated Cd-contaminated soils

The soil cadmium (Cd) contamination is a ubiquitous environmental problem that has resulted from intense irrigation with wastewater. This pot trial was conducted with aim to produce safe food with Cd tolerant wheat cultivar in wastewater irrigated soils. For this purpose, two wheat cultivars NARC-2011 (Cd tolerant) and Shafaq-2006 (Cd sensitive) were screened out and selected, after conducting a pilot trial of twelve local wheat cultivars against Cd stress. Both cultivars were grown in naturally contaminated soils with Cd concentrations (4.18, 3.23, 2.29 and 1.25 mg kg−1). After harvesting, NARC-2011 showed significant photosynthetic attributes, grain biochemical parameters and yield. Additionally, Cd concentrations in edible grains of NARC-2011 cultivars were found within standard limits (200 mg kg−1), in all contaminated soils. Furthermore, a marked decrease in Cd bioavailability was noted with cultivar NARC-2011, where contribution of mobile Cd fractions (exchangeable and reducible) percentage was decreased, while immobile Cd fractions percentage increased (oxidizable and residual). Fourier transform infrared (FTIR) spectroscopy reflects the maturity and stability of humic and fulvic like acid fractions and revealed that humification of these compounds after prolonged sludge enriched wastewater irrigation lowered the Cd availability. The wheat cultivar NARC-2011 (Cd tolerant) could be opted to grow on soils irrigated with wastewater for a long time, as Cd bioavailability decreased with ageing due to stabilized humic substances and varietal tolerance.

Effects of land use on groundwater recharge of a loess terrace under long-term irrigation

Understanding the relation between land use and groundwater recharge is of direct interest in areas that are prone to geohazards. This study was performed to characterize the effects of land use on groundwater table (GWT) distribution in the Heifangtai (HFT) loess terrace under long-term flood irrigation, as irrigation intensity was governed by the crop types. In light of the regional temperature-vegetable dryness index (TVDI) and optical images obtained in different seasons over four years, the dataset incorporated the growth cycles of the local crops, which in turn improved the workload and accuracy of land use detection. Irrigation intensities for different crops were recorded during field investigations. A total of 26 electrical resistivity tomography (ERT) profiles were conducted to estimate the GWT distribution of HFT terrace, which was further utilized to reveal the relation between land use (i.e. irrigation) and GWT fluctuations. The results indicated that high local GWT was associated with vegetable fields which had the highest irrigation intensity, and by contrast, low local GWT was attributed to the perennial fruit tree fields with the lowest irrigation intensity. The discharge was monitored intermittently for over three years to analyze the effect on the local GWT close to margin of HFT. The result showed a strong correlation between spring discharge and GWT fluctuations along the margin of HFT, indicating that groundwater recharge was affected by both irrigation and spring discharges. These results suggested that incorporating growth cycles of crops can effectively facilitate the interpretation of remote sensing data for land use detection, and the results can provide useful guidance for improving irrigation programs and for alleviating geohazards in regions that are under long-term irrigation.

Transformations in the Agricultural and Scenic Landscapes in the Northwest of the Region of Murcia (Spain): Moving towards Long Awaited (Un)Sustainability

Since the middle of the 20th century, irrigation in the southeast of Spain has displayed significant productive growth based on the intensive use of the scarce water resources in the area and the contribution of river flows from the hydrographic basin of the Tagus River to the hydrographic basin of the Segura River. Despite high levels of efficiency in the water use from the new irrigation systems, the water deficit has only intensified in recent years. The most dynamically irrigated areas (Campo de Cartagena, Valle del Guadalentín, Vega Alta del Segura and the southern coast of the Region of Murcia), were faced with a complex and trying future, resulting in numerous companies (agribusinesses) relocating to lease and acquire land in the northwest of Murcia to develop their intensive crops. The general objective of this article lies in the analysis of widespread landscape dynamics, and of agricultural dynamics in particular, in the rural environment of the northwest Region of Murcia (Spain). For this, an exhaustive analysis of the land cover and use transformations is carried out for the periods of time 1990–2000–2012–2018. The data studied come from the Corine Land Cover (CLC) project, carried out by the European Environment Agency (EEA). These spatial data are treated with geographical information systems (GISs) and represented by statistical and cartographic analyses and cross-tabulation matrices that indicate the dynamics of changes, loss and land gain. As the main result, we find that the areas occupied by new intensive irrigation on old rainfed farmland in the northwest Region of Murcia have increased in the last 30 years. Traditional irrigation is disappearing, and the environmental consequences (overexploitation of aquifers and decreased flows from natural sources), among others, are dire.